Hi, I am hesitant to call the following a bug. It might just be a misunderstanding on my side. Anyhow...
I am plotting a normal line collection and an "axvline" collection on the same Axes. The latter is a collection of lines with data coordinates for x and axes coordinates for y, using a blended transform. I find that the data limits are messed up by the axvline collection, which unexpectedly sets the bottom y limit to 0. This results in a badly scaled plot when adjusting the view with autoscale_view. Interestingly, this problem goes away if the normal line collection is viewed first via autoscale_view, if the normal line collection is replaced by a normal plot command, or if the axvline collection is replaced by a normal axvline command. The problem appears if the two collections are added to the Axes without an autoscale_view in between. I ran the code below with matplotlib trunk (SVN r8646) on Mac OS 10.5 with TkAgg backend. The same behaviour appears in matplotlib 0.99.1.1. Please let me know if I am doing something obviously stupid, especially in the way I create the axvline collection. At the moment I am working around the behaviour by inserting an autoscale_view between the two collections, so it is not a major show-stopper. Regards, Ludwig ### Start code snippet ### import matplotlib as mpl import matplotlib.pyplot as plt import numpy as np # Create sine wave to plot (offset from zero) t = np.arange(200) x = 10 + np.cos(2 * np.pi * t / 20) plt.figure(1) plt.clf() ax = plt.gca() # Add main plot as a line collection containing one segment segments = mpl.collections.LineCollection([zip(t, x)]) ax.add_collection(segments) print ax.dataLim # Output: Bbox(array([[ 0., 9.], [ 199., 11.]])) # Uncommenting the line below actually fixes the problem... #ax.autoscale_view() # Add break lines as a collection of axvlines breaks = np.arange(0, 200, 20) transFixedY = mpl.transforms.blended_transform_factory(ax.transData, ax.transAxes) break_lines = mpl.collections.LineCollection([[(s, 0), (s, 1)] for s in breaks], transform=transFixedY, colors='k', linewidths=0.5, linestyles='dotted') ax.add_collection(break_lines) print ax.dataLim # Output: Bbox(array([[ 0., 0.], [ 199., 11.]])) # Notice that y0 is now 0 instead of the expected 9 # Autoscaling now inserts a lot of space below the original plot ax.autoscale_view() ### End code snippet ### ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
